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Diffstat (limited to 'llvm/docs/CommandGuide/llvm-profdata.rst')
| -rw-r--r-- | llvm/docs/CommandGuide/llvm-profdata.rst | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/llvm/docs/CommandGuide/llvm-profdata.rst b/llvm/docs/CommandGuide/llvm-profdata.rst index 210826a7bab..74fe4ee9d21 100644 --- a/llvm/docs/CommandGuide/llvm-profdata.rst +++ b/llvm/docs/CommandGuide/llvm-profdata.rst @@ -28,7 +28,7 @@ MERGE SYNOPSIS ^^^^^^^^ -:program:`llvm-profdata merge` [*options*] [*filenames...*] +:program:`llvm-profdata merge` [*options*] [*filename...*] DESCRIPTION ^^^^^^^^^^^ @@ -37,6 +37,14 @@ DESCRIPTION generated by PGO instrumentation and merges them together into a single indexed profile data file. +By default profile data is merged without modification. This means that the +relative importance of each input file is proportional to the number of samples +or counts it contains. In general, the input from a longer training run will be +interpreted as relatively more important than a shorter run. Depending on the +nature of the training runs it may be useful to adjust the weight given to each +input file by using the ``-weighted-input`` option. + + OPTIONS ^^^^^^^ @@ -49,6 +57,13 @@ OPTIONS Specify the output file name. *Output* cannot be ``-`` as the resulting indexed profile data can't be written to standard output. +.. option:: -weighted-input=weight,filename + + Specify an input file name along with a weight. The profile counts of the input + file will be scaled (multiplied) by the supplied ``weight``, where where ``weight`` + is a decimal integer >= 1. Input files specified without using this option are + assigned a default weight of 1. Examples are shown below. + .. option:: -instr (default) Specify that the input profile is an instrumentation-based profile. @@ -75,6 +90,30 @@ OPTIONS Emit the profile using GCC's gcov format (Not yet supported). +EXAMPLES +^^^^^^^^ +Basic Usage ++++++++++++ +Merge three profiles: + +:: + + llvm-profdata merge foo.profdata bar.profdata baz.profdata -output merged.profdata + +Weighted Input +++++++++++++++ +The input file `foo.profdata` is especially important, multiply its counts by 10: + +:: + + llvm-profdata merge -weighted-input=10,foo.profdata bar.profdata baz.profdata -output merged.profdata + +Exactly equivalent to the previous invocation (explicit form; useful for programmatic invocation): + +:: + + llvm-profdata merge -weighted-input=10,foo.profdata -weighted-input=1,bar.profdata -weighted-input=1,baz.profdata -output merged.profdata + .. program:: llvm-profdata show .. _profdata-show: |
